A workpiece is known from German utility model patent G 88 00 461.9, with which an edging strip can be mounted on the narrow, circumferential edge of a table-shaped workpiece. Clamping jaws are provided in a clamping jaw support known as a yoke. The yoke has forked legs. The clamping jaws are pivot-mounted about parallel axes through the forked ends of the legs of the yoke.
In this device the workpieces to be clamped the open space between the legs of the yoke.
Another workpiece clamp is disclosed in U.S. Pat. No. 5,350,163. It has clamping jaws which can be adjusted by sliding in guide grooves. These guide grooves are arranged on a clamping jaw support in symmetrical and V-shaped fashion relative to one another. When clamping a workpiece, the clamping jaws move in the direction of the tapering guide grooves. This results in a wedge effect, which primarily serves to clamp the workpiece. The V-shaped arrangement of the guide grooves makes it possible to use the to clamp a relatively wide range of workpiece thicknesses. However, this device is also limited to workpieces which can only extend freely on the side of the clamping jaw support on which the jaws are mounted.
The function of this device disadvantageously requires that the clamping jaws arranged in the symmetrical guide grooves be positioned exactly opposite one another when approaching a workpiece. If the clamping jaws are not exactly opposite one another, this leads to a situation where one of the clamping jaws moves in one direction in its guide groove and the opposite clamping jaw in the other direction, when pressing on the workpiece. This causes the workpiece to rotate and prevents it from being clamped. In order to be able to handle this clamp clip despite these difficulties, it is provided with an auxiliary device with which the clamping jaws can always be moved in the guide grooves in a symmetrical position relative to one another.
In order for the bearing pins of this device to always remain in a vertical position, the guide grooves and the bearing pins guided in them must be manufactured with great precision. Any play in the bearing pin caused by wear quickly makes the device unserviceable. The particular accuracy and care involved in the manufacture of the numerous individual parts required and in the assembly of this device lead to high manufacturing costs. The auxiliary device required to symmetrically guide the clamping jaws further increases manufacturing costs. and also increases the weight of the device which makes handling difficult.
A general object of the present invention is to overcome certain disadvantages of the prior art and to provide a clamp with which long plate-shaped and/or bar-shaped workpieces can be clamped, where both the first and second workpieces can be of plate-shaped design.